so can i run fcom with qarl's texture pack and better cities in high settings

intel core i5 2400 3.10 GHz
4gb RAM
GTS 450 (factory overclocked) 1gb dedicated VRAM

i worry though i don't have a separate sound card, and oblivion wiki suggested to have one

i can also opt to add more ram but currently oblivion can only handle a maximum of 4gb by using the 4gb patch

yes sorry i forgot, i'm on win 7 64 bit

Do you have a 64bit OS? The 4Gb LAA patch is a waste if you don't.

I highly recommend you use Qarl's Texture Pack 3 Redimized, it optimizes all the textures for improved VRAM efficiency with no loss in visual quality. Especially since you will be using Better Cities.

Wrye Bash comes with its own Quiet Feet tweak in the Bashed Patch now, so if you experience any major slowdowns around creatures, you can always try that.

The overclocked GPU concerns me a bit, because Oblivion is known to react badly to overclocked hardware, but other than that, I see no reason why you can't run the above.

Are you planning to run any of the city mods that add inhabitants? Because the combination of these and BC are sure fps killers, regardless of processing power. Just a word of advice, in advance: choose either BC, or the inhabitants ones. You'll see fps losses in any case, but they should be bearable.

I'm presuming you are on Win7.

You probably could get away with this, provided you use QT3 Redimized, but you'll need to be really careful to not add too much other stuff that will up you texture usage, as with what you're planning to run you'll probably be easily able to blow the VRAM and overload your RAM leading to crashes. If you could grab yourself a couple of extra gigs of RAM it should help you big time.

Generally though, you should be fine, just proceed with caution.

Win7? That really gulps memory. Try to disable as many special visual effects and (only) unnecessary services as possible before playing.

I am still of the firm belief that if you're going to use the LAA patch you should only do so on a system with more than 4GB of ram because otherwise Windows will eat up too much of it to matter. Even if you go around shutting things down before playing.